For the Consumer

As well as its needed effects, midazolam (the active ingredient contained in Versed) may cause unwanted side effects that require medical attention.

If any of the following side effects occur while taking midazolam, check with your doctor or nurse immediately:

Less common

Anxiety

chest pain or discomfort

choking

confusion

difficult or troubled breathing

drowsiness

dry mouth

fast heartbeat

hyperventilation

irregular heartbeats

irregular, fast or slow, or shallow breathing

irritability

lightheadedness, dizziness, or fainting

nausea

nervousness

noisy breathing

pale or blue lips, fingernails, or skin

restlessness

shaking

shortness of breath

slow or irregular heartbeat

tightness in the chest

trouble sleeping

unable to speak

unusual tiredness

weakness

wheezing

Rare

Attack, assault, or force

changes in patterns and rhythms of speech

feeling of constant movement of self or surroundings

headache

lack or loss of self-control

loss of balance

mood swings

noisy breathing

not breathing

restlessness

seeing, hearing, or feeling things that are not there

sensation of spinning

shakiness and unsteady walk

sleepiness

slow to respond

slurred speech

trouble in speaking

unconsciousness

unsteadiness, trembling, or other problems with muscle control or coordination

If any of the following symptoms of overdose occur while taking midazolam, get emergency help immediately:

Symptoms of overdose

Change in consciousness

difficulty with coordination

loss of consciousness

sleepiness or unusual drowsiness

Some midazolam side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:

For Healthcare Professionals

Respiratory

Respiratory side effects, which have included cardiorespiratory depression, apnea, and respiratory arrest, are extensions of the drugs pharmacologic activity.[Ref]

Personnel and equipment necessary for the treatment of respiratory depression and arrest should be immediately available whenever midazolam is administered.

One retrospective study has reported that the frequency of respiratory arrest (in nonventilated patients) is 0.099%. This study reported that respiratory arrest was associated with high doses of midazolam, concurrent administration of opioids, and advanced age.

Another study has reported that midazolam causes a decrease in tidal volume, an increase in breathing frequency and no change in minute ventilation in healthy volunteers. That study, however, did report a significant increase in CO2 retention following midazolam administration.[Ref]

Cardiovascular

Cardiovascular side effects including alterations in blood pressure, arrhythmias, and ventricular irritability have been reported. Hypotension and decreases in systemic vascular resistance have been reported most frequently; however many investigators have reported minimal cardiovascular effects following administration of midazolam (the active ingredient contained in Versed) [Ref]

Local

Local side effects at the site of injection (local flare reactions, pain, burning, phlebitis, local irritation and swelling) have been reported in up to 12% of patients. Vascular impairment after inadvertent intra-arterial injection is a theoretic concern.[Ref]

Although local effects have been reported frequently, many clinicians believe that midazolam is the least likely of the commonly available injectable benzodiazepines to result in local reactions.[Ref]

Gastrointestinal

Gastrointestinal side effects including nausea, vomiting, and hiccups have each been reported in about 3% of treated patients.[Ref]

Nervous system

Nervous system side effects have included acute dystonia. One study (n=113) has reported that orally administered midazolam (the active ingredient contained in Versed) produced significant anterograde amnesia when administered as early as ten minutes before a surgical procedure.[Ref]

Psychiatric

Psychiatric side effects have included a variety of adverse behavioral effects such as disinhibition (especially sexual disinhibition), hostility, rage reactions, restlessness, aggressiveness, and paroxysmal excitement.[Ref]

Other

Other side effects including cases of benzodiazepine withdrawal symptoms (myalgias, tachycardia, and anxiety) have been reported in patients who have received multiple or continuous doses of midazolam (the active ingredient contained in Versed) In such patients, abrupt discontinuation is not recommended.[Ref]

Immunologic

Immunologic side effects including pruritus, angioedema, and bronchoconstriction have been reported rarely.[Ref]

Endocrine

Endocrine side effects have included decreases in the secretion of cortisol and insulin.[Ref]

Professional resources

Related treatment guides

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